Violence Reverses Gains in Iraq

By

Matt Bradley and

Ali A. Nabhan

Oct. 24, 2013 7:37 p.m. ET

BAGHDAD—A flurry of recent attacks by al Qaeda-linked militants in Iraq—strengthened by their alliance with jihadist fighters in Syria—is threatening to undo years of U.S. efforts to crush the group, widening sectarian conflict in the Middle East.

The chaos across the border in Syria and Iraqi Sunnis' feeling of discrimination under the Shiite-led government has reignited the kind of intense sectarian strife that brought Iraq to the...